How can i change proxy settings on computer

Your PC has a proxy setup for your 'network'. Ok, to disable a proxy you simply:

1. From IE, in the menu bar, select Tools then 'Internet Options'. Then click on the 'Connections' tab. Near the bottom click on the button 'LAN settings'.

2. Under Proxy server, uncheck the checkbox for 'Use a proxy server for your LAN'.

3 Click Ok on both windows to save your changes.

4. If this option is ghosted, or you cannot navigate to this setting, then Group Policy is probably being enforced and you will not be able to change the settings. See your network administrator about this.

If you are using a separate proxy software, then you would need to review the procedures in the documentation of the software itself.
Source(s):
memories...from the corners of my mind. Answered Dec, 27 2010

you can reference this address :windows.microsoft.com/en-US/windows-vista/Change-proxy-settings-in-Internet-Explorer Answered Feb, 20 2011

Open Internet Explorer by clicking the Start button , and then clicking Internet Explorer.

Click the Tools button, and then click Internet Options.

Click the Connections tab, and then click LAN settings.

Select the Use a proxy server for your LAN check box.

In the Address box, type the address of the proxy server.

In the Port box, type the port number.

If your network requires separate proxy addresses for different services, such as HTTP, HTTPS, or FTP, click the Advanced button, and then type the individual proxy server addresses to use.

When you are finished making changes, click OK until you return to Internet Explorer.

from http://windows.microsoft.com/en-US/windows-vista/Change-proxy-settings-in-Internet-Explorer Answered Mar, 31 2011